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6.4 Properties of Rhombuses, Rectangles, and Squares. A rhombus is a parallelogram with four congruent sides. A rectangle is a parallelogram with four right angles. A square is a parallelogram with four congruent sides and four right angles. Special Parallelograms. Theorem 6.13.
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6.4 Properties of Rhombuses, Rectangles, and Squares • A rhombus is a parallelogram with four congruent sides. • A rectangle is a parallelogram with four right angles. • A square is a parallelogram with four congruent sides and four right angles.
Theorem 6.13 • If a parallelogram is a rhombus, then its diagonals are perpendicular.
Theorem 6.14 • If a parallelogram is a rhombus, then each diagonal bisects a pair of opposite angles.
Finding Angle Measures • What are the measures of the numbered angles in rhombus ABCD?
Theorem 6.15 • If a parallelogram is a rectangle, then its diagonals are congruent.
Finding Diagonal Length • In rectangle RSBF, SF = 2x + 15 and RB = 5x – 12. What is the length of a diagonal? SF = RB 2x + 15 = 5x – 12 27 = 3x x = 9 SF = 2x + 15 SF = 2(9) + 15 SF = 18 + 15 SF = 33
More Practice!!!!! • Homework – Textbook p. 379 – 380 # 1 – 39 ALL.